High performance vehicles, for example high performance aircraft and aircraft undergoing testing and research and development, require a reliable, accurate and robust sensor and telemetry system in order to provide real-time operational condition feedback of the measurement data collected by the sensors. This data may be sent as continuous telemetry and/or collected in a central data collection unit for subsequent downloading. Alternatively, the data collected may be stored within the sensor itself, and subsequently transmitted to the central data collection unit at a specific time. Or it may be required to collect data individually from each sensor using a portable computer.
One problem associated with current sensing systems for high performance vehicles is that current commercially available non-wired sensors are large and bulky. This severely limits the locations where such non-wired sensors can be installed upon and/or within the vehicle.
Another major problem with wireless sensors is that none of the commercially available ones can reliably communicate in real-time over long distances at a sufficient data transfer rate. The more extreme the operational parameters of the vehicle become, such as speed, component stress, altitude and the like, so too does the problem of being able to send and receive real-time data transmissions. The problem is exacerbated when the number of sensors fitted to the vehicle is increased.
To overcome these problems, current sensors typically require wiring to at least provide power to the sensor, and typically also to provide a path for the data acquired by the sensor to be sent to a separate data logger at a sufficient data transfer rate.
However, on certain types of vehicles, such as aircraft for example, the fitting of wired sensors can take weeks, or even months to install and commission. This adds significantly to the cost, both direct and indirect, related to having such a high value asset out of commission during the fitting and commissioning phases.
To overcome these problems, ideally it would be preferable to use suitable wireless sensors that are certified for use on both the exterior and interior surfaces of an aircraft, but currently these do not exist. Because of their bulk, the existing types of wireless sensors for use on aircraft can only be installed at limited interior structural locations of the aircraft. This typically requires disassembly of aircraft structures to provide the necessary access for installation and removal of the wireless sensor(s). The same problem thereby arises. There is a substantial direct and indirect cost associated with having an expensive asset, such as an aircraft, out of commission for an extended period of time. It also requires highly qualified specialist aircraft engineers to perform the task of aircraft disassembly, and re-assembly, plus the need to have the aircraft re-certified for flight after the re-assembly has been completed.
Further to this, no existing sensor system that is currently available can be directly mounted onto coated external aircraft surfaces, and subsequently removed, without damage to the aircraft coating. Removal of the original coatings to enable sensor installation, and the subsequent repair required, also add significant time and cost. For example, all currently available strain sensors require the strain gauge sensor itself to be mounted directly onto cleaned bare metal surfaces. Strain gauge sensors are typically very fragile and therefore require specialised technicians to install.
Traditional wired sensors may be smaller than their non-wired counterparts, but when wired sensors have the advantage with size, they have the disadvantage of adding the weight of the associated wiring that is required for them to operate. It is not uncommon for an installed system to consist of several kilograms of wiring. Most often, the aircraft structure needs to be permanently modified to accommodate the sensing system and its associated equipment and wiring. When an aircraft is modified in this way, it often needs to have its airworthiness re-certified. Air-worthiness certification is both time consuming and very costly.
Also, modified aircraft often become “orphan aircraft” because of their unique modified structures and require individualised maintenance and sustainment plans which are costly and inefficient, thereby making them a burden on aircraft maintenance resources and scheduling. All this substantially increases the cost and time associated with acquiring real time flight performance data, both in direct costs, and in the ancillary costs surrounding specialised maintenance and recertification.
Dedicated test aircraft are also known as “orange wired” aircraft. As modern aircraft, particularly high performance aircraft and aerospace vehicles, continue to become significantly more expensive, many national defence budgets are unable to afford the significant costs associated with new generations of dedicated test aircraft. Orange wired aircraft are significantly more expensive than regular aircraft. Due to this significant extra cost, both in acquiring and maintaining them, they are often minimally used to preserve their integrity, and to reduce their wear and tear, and to keep the aircraft within its airworthiness lifespan for as long as possible. This type of special treatment often means that there is a disconnect between the flight characteristics of an orange wired aircraft over that of a regular aircraft of the same make and model. The data acquired from the operation of orange wired aircraft may not be truly representative of the operations of the entire regular fleet. Furthermore, only acquiring data from one particular aircraft means that the amount of data collected is somewhat limited and may have an undesirable impact on any engineering analysis of that data. Furthermore, sensors that are placed on an aircraft, and especially those placed on the outside of aircraft, particularly on any of its wings and/or flight control surfaces, require flight safety certification.
In addition to the aforementioned problems, stealth is now a major design consideration in many designs of military aircraft, particularly high performance military aircraft. Two critical factors that directly relate to the stealthiness of a particular aircraft design are its shape and the type of coating on the skin of the aircraft. Many advanced coatings have either been developed already, or are under development, that provide a high level of RADAR signal absorption, and this coating cannot be either removed or damaged in relation to the installation of, or removal of, any of the sensors and/or its ancillary equipment. Furthermore, the installation of the sensors and/or its ancillary equipment cannot significantly alter the shape of the aircraft so that its stealth performance is compromised in any way.
Very high performance vehicles, such as aircraft, require a large variety of flight characteristic parameters to be monitored. As the performance of these vehicles increases with each generation designed and manufactured, the number of parameters requiring sensor data increases. However, no existing sensor system that measures a wide multitude of parameters within one single sensor package is currently available commercially for aircraft testing applications. Examples of the types of parameters that need to be sensed, often at multiple locations on the aircraft's airframe, include acceleration, strain, temperature, humidity, pressure, inertia, and magnetic fields. Currently, should a user require the measurement of a large number of parameters at one single location, they have to install multiple sensor units at that location. This contributes to increased bulk, weight, and power requirements. Moreover, none of the currently available sensor systems are suitable for use on external surfaces of an aircraft during flight. This includes
a) Subsonic flight
b) Transonic flight
c) Supersonic flight
Current sensor systems in use are configured while the aircraft is on the ground. Because of the complexity involved in system configuration procedures, and the lack of a suitable interface, they cannot be easily reprogrammed, or the measured data quickly analysed in real-time by the flight crew during the flight. This is particularly the case in single or two seat aircraft that lack a dedicated team of test engineers on-board, solely responsible for the management of the sensor system, and evaluation of the data obtained.
It is therefore an object of the current invention to provide a novel and inventive sensor and associated telemetry system for high performance vehicles, such as an aircraft, or an aerospace vehicle, that at least ameliorates some of, or all of, the aforementioned problems.